It is known to maintain pressure between the skin and the vibrator output element by means of magnets/magnetisable parts implanted subcutaneously and in the vibrator output part respectively. However, the constant pressurisation of the skin between the implanted parts and the vibrator may cause pressure wounds or irritation of the skin.
The prior art transcutaneous vibration transmission systems applies a relatively large plate with magnets facing the skin. This relatively large plate will act as a speaker membrane that will acoustically emit sound. This acoustical sound path has negative effects on feedback margins for the hearing aid system. This relatively large plate will have a relatively large mass that will create a mechanical impedance mismatch when transferring mechanical vibrations from the vibrator through the skin to the bone.
US 20130018218 A1 suggests several solutions to the problem (pressure wounds or irritation of the skin) of the constant pressurisation of the skin between the implanted parts and the vibrator: such as ameliorate the attraction power between external and internal parts by adjusting the distance between the skin surface and the external magnetic parts, or such as adding a soft cushioning layer between the magnetic parts and the skin or molding the parts abutting the skin by to follow the skin surface.
US 20130018218 A1 does not provide a solution to the problems caused by the transmission of the vibrations through the rather heavy magnets provided between the vibrator output and the skin surface.
Thus there is need for a transcutaneous vibration transmission system that reduces or even eliminates these drawbacks of the prior art.